Occurrence of Francisella tularensis palaearctica bacteriuria in a wild vole on one occasion was reproduced experimentally by vaccination of voles with a strain of attenuated virulence and subsequent challenge with a fully virulent strain. Subsequently, chronic bacteriuria was reproduced by oral infection of naive voles with virulent strain organisms only, although one organism introduced parenterally is sufficient to cause fatal infection. The oral route of infection is a common one for voles, and voles are, apparently, universally present wherever lotic waters are contaminated by F. tularensis. Bacteriuria in voles is proposed as the important source of that contamination which is sometimes a source of extensive epidemics. Pyelonephritis caused by ingestion of the organisms is undoubtedly hematogenous and could be a sought after model of that disease although the current consensus is that pyelonephritis in humans is the result of ascending infection.